This invention relates to a cylinder injection type internal combustion engine and more particularly to an injection system that injects fuel and pressurized air into the combustion chamber and to a method of operating an engine employing such a fuel air injector.
The advantages of direct cylinder fuel injection are well known. It has been proposed to improve the performance of a two cycle internal combustion engine by direct cylinder fuel injection. In order to improve atomization of the fuel and reduce hydrocarbon emissions, compressed air is added to the cylinder along with the injected fuel.
In systems that employ both fuel and compressed air injection, however, the engine tends to become quite complicated. That is, in addition to the normal fuel injection system, there must be provided a source of compressed air. This generally requires the use of an air compressor, pressure regulator and air distribution line. Such complication of the engine is, of course, undesirable.
It has been further proposed to employ as a pressurized gas source, a portion of the compressed gases that had been ignited in another cylinder of the engine. That is, one cylinder which is burning and undergoing the expansion and scavenge cycle has a portion of the expanding gases charged into an accumulator which is utilized to inject fuel into another cylinder of the engine at the time of fuel injection. Although such arrangements provide some simplification in that they do not require an air compressor, the conduitry required to communicate various cylinders with each other does provide some complications. Furthermore, the compressed charge which is employed is formed of both fuel and air and which have been at least partially burned. As a result, the charge is at a high temperature and also may include foreign particles, such as carbon or the like, which can give rise to obvious problems.
It is, therefore, a principal object of this invention to provide an air fuel injection system for an engine in which a separate source of compressed air is not required and in which the air which is employed for fuel injection is compressed within the same combustion chamber of the engine but which does not contain any substantial amount of combustion products.
It is a further object of the invention to provide an improved injector of this type which can be utilized with a two cycle internal combustion engine.
It is a further object of this invention to provide a fuel air injector for an internal combustion engine and method of operating an engine wherein the compressed air for the fuel injector is supplied to the injector directly from the cylinder of the engine into which it injects.